Leading U.S. officials say they believe Washington and Beijing can work together toward resolving environmental problems, which are expected to increase along with China's growing economy.

China faces environmental challenges, across the board.

"Whether it's air quality, or water quality or availability, or land degradation, China's facing a very serious set of problems," said Elizabeth Economy of the Council on Foreign Relations.

She testified Thursday before the U.S.-China Economic and Security Review Commission.

"But, I think, if you were to ask anybody in China what the most serious environmental challenge that they face is, they would focus on the issue of water," she added. "About one third of the water that flows through China's seven major river systems and their tributaries is not even suitable for agriculture or industry. [About] 300 million people drink contaminated water on a daily basis. [Of that number] 190 million of those, and these are Chinese statistics, 190 million of those drink water so contaminated that it is making them sick."

Economy adds that environmental problems in China are not only a major internal problem, but also greatly affect other countries.

"Just to give you a sense of some of the implications that we are seeing, one of the most recent changes is that China has now become a significant contributor to marine pollution," she added. "In the Yangzi River Delta, 50 percent of the sewage is discharged untreated, and flows into the Pacific. In terms of trans-boundary air pollution, both in terms of acid rain and contaminated dust, clearly Japan, South Korea have long been affected. And, the United States, periodically, has also been affected from this contaminated dust."

In his testimony to the commission, the Environmental Protection Agency's Jerry Clifford said Washington has been concerned about the state of China's environment.

"Our challenge, here in the U.S., is that their pollution is ultimately affecting the lives and the public health of citizens in the United States," he noted. "That's what drives our interest in China. And, to that end, that's where we hope to be able to help them make improvements."

He pointed to a lack of manpower as one of China's main problems.

"We have roughly 18,000 people at the EPA," he added. "They have less than 500 people in their State Environmental Protection Administration. They are able to tap - that's bolstered because they're able to tap in to some of the research organizations for the research part of the work. But their ability to enforce their laws and regulations is modest, at best, with those type of resources."

Clifford said the EPA's work with China has increased dramatically over the last few years. He added that the Chinese government has what he described as "very solid laws on the books at the national level" to protect the environment. But he added that a serious stumbling block is implementing those laws, standards and regulations at the local level.